textproduct: Rapid City

KEY MESSAGES

- Isolated thunderstorms are possible across portions of northeastern Wyoming and southwestern South Dakota this evening. Gusty winds will be possible.

- Above average temperatures will return for the second half of the week. The warmest days will be Friday and Saturday with highs in the mid to upper 90s.

- Elevated to near-critical fire weather conditions are expected through Saturday.

DISCUSSION

(This Evening Through Wednesday) Issued at 146 PM MDT Wed Sep 2 2026

Upper air analysis shows ridging over the Ohio Valley, with the main axis just crossing into the eastern Dakotas. A strong upper low just offshore the Pacific NW coast is bringing active southwesterly flow to much of the western CONUS, including the CWA. A shortwave is crossing WY at this time, with isolated showers and thunderstorms developing over the last two hours. Surface obs (and even the KUDX radar) show nicely a warm front pushing into the Black Hills and southerns SD. Temperatures have risen into the 90s behind the front, along with dewpoints dropping from the 60s over the western SD plains into the 40s. This front will continue northeastward through most of the CWA by late evening. Storms may make it into the CWA...especially the SW portions. Because of the drier air moving in, instability is rather weak. However, inverted boundary layer profiles behind the front would support gusty winds. If storms make it across the CWA border, can't rule out some gusts making it above 50 mph (as has already occurred in the CYS CWA). While instability is much higher ahead of the warm front, so is the cap...so storms are not expected to be an issue toward NW SD. The warmer, drier air will continue to advect in through Thursday morning. Highs will reach into the upper 80s and 90s with mostly sunny skies. A second reinforcing shot of hot, dry air will be drawn into the CWA Friday morning ahead of a strengthening surface low over MT. Temps well into the 90s...and even nearing 100...are possible Fri and Sat. After Saturday, models diverge with what next week will look like. The spread of solutions generally range from near average to well above. Climatologically, early to mid September tends to bring a noticeable shift toward cooler, more autumn-like (aka mild) weather. Both the 12z GFS and ECMWF are finally hinting at this with a cold front pushing through during the first half of next week. Will be interesting to see where models settle over the next few days.

AVIATION

(For the 00Z TAFS Through 00Z Thursday Evening) Issued At 507 PM MDT Wed Sep 2 2026

Gusty southwesterly winds will continue to diminish this evening. Isolated showers and thunderstorms are possible over northeast Wyoming and western South Dakota through 03/05z. Transient MVFR conditions are possible around any heavier precipitation cores and gusty/erratic winds can be expected with any stronger convective cores. VFR conditions are expected through the TAF period outside of any showers/thunderstorms.

FIRE WEATHER

Issued At 146 PM MDT Wed Sep 2 2026

Warmer and much drier air is moving into the northeastern WY and southwestern SD and will continue across the rest of western South Dakota this evening. Temperatures will increase through the rest of the week with highs well into the 90s. Very dry humidity is also expected, dropping to near or below 15 percent across northeastern WY and portions of far western SD. With southwesterly winds gusting up to 30 mph expected Thursday afternoon, have issued a Red Flag Warning for Campbell and most of Weston County in NE WY. Elevated to near-critical fire weather conditions are expected elsewhere through Saturday.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...Red Flag Warning from noon to 8 PM MDT Thursday for WYZ314-315- 317.